Toll apparatus for telephone-exchanges.



No. 710,3l8. A Patented Sept. 30, 1902..

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TOLL APPARATUS FOR TELEPHONE EXCHANGES.

(Application filed Jan. 14, 1902.)

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WILLIAM W. DEAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO WESTERN ELEC TRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TOLL APPARATUS FOR TELEPHONE-EXCHANGES.

SPECIFICATION forming part of Letters Patent No. 710,318, dated September 30, 1902. Application filed January 14, 1902. Serial No. 89,657. (No model.)

1'0 all whom it may concern: trolled through the agency of a switch at the Be it known that I, WILLIAM W. DEAN, a calling-subscribe1"s station, associated witha citizen of the United States, residing at Chitoll device, such as a manually-operated concago, in the county of Cook and State of Illinection-register, is provided for reversing or 55 5 nois, have invented a certain new and usecounteracting said device to reestablish the ful Improvement in Toll Apparatus for Teleflow of current through the transmitting-tele phone-Exchanges, (CaseNo. 36,) of which the phone, so that the telephone apparatus may following is a'full, clear, concise, and exact be restored to its operative condition by acdescription. tuating the register. The centralized talk- 60 My invention relates to toll apparatus for ing-battery is usually applied in a bridge telephone-exchanges; and its object isin genbetween the line conductors at the exchange eral to provide means whereby a charge may office, between the windings of the repeatingbe made for each use of a subscribers telecoil of the operators plug-circuit with which phone in originating a connection in which connections are made; and in the preferred 65 the subscriber is actually placed in commuform of myinvention the operatoris furnished nication with the party called for. with a blocking-switch adapted to be manu- My invention contemplates the employally set for changing the connections of the ment of a toll device at the substation of a battery with the lineas, for instance, cuttelephone-line, adapted for manual operation ting off one of the line conductors from its 70 by the subscriber, and a blocking device normal battery connection and connecting adapted to be actuated at the central office said conductor with the other pole of the batin the course of making connection from the tery to which the other line conductor is conline in question to another to render telenected. In otherwords,bothlineconductors phonic communication over the line imposmay be connected by the switch aforesaid 75 sihle until the subscriber has operated his with the same pole of the battery. The optoll device, said toll device when actuated posiie pole of the battery is grounded. The serving to bring about the operation of mechsubscribers telephone transmitting apparaanisni which restores or counteracts the blocktus, which is includedin circuit between the ing device. The subscriber may be relieved two sides of the lines at the substation, may 80 of the special act and no charge made when thus be deprived of current, so blocking the a connection called for cannot be made or use of thetelephone. Theswitch whicheffects when the line is used in response to calls this change in the battery connections may from other stations, the blocking device in be set manually by the operator and may be such cases not being set. restored automatically by a magnet which is 85 5 My invention is designed especially for use controlled through the agency of a flow of in modern telephone-exchanges wherein a current in one of the line conductors. The common source of current is provided at the flow of current for controlling therelease of central office of the exchange for supplying the central-oflice blocking-switch may be dethe substation transmitting instruments of all termined by mechanism actuated in the opera- 90 0 the lines of the system, the current being sent tion of the subscriber toll device. After the out to the substation over the line conductors blocking-switch has been set at the central during the period of use of the telephones. office the subscriber may therefore restore the In accordance with myinvention the supply operative conditionot'his telephoneapparatus of current for the subscribers transmittingby actuatinghis connection-register. In the 5 telephone is controlled by a device adapted preferred form of my invention the magnet to be actuated at the central office in the which controls the release of the blockingcourse of the establishment of telephonic cornswitch is included in a local circuit'controlled munication with another subscriber, Wherejointly by two relays, one of said relays being by the calling-subscribers telephone may be in circuit with each limb of'the line, and the 10c rendered inoperative by depriving it of curtoll device at the substation is provided with rent, and electromagnetic mechanism conswitch mechanism arranged to establisha certain electrical condition of each limb of the line independent of the other limb, whereby said relays may be controlled independently. The relays can be arranged to close the circuit of the releasing-magnet onlywhen one of said relays is excited and the other inert, and this condition can ordinarily be brought about only through the operation of the switching mechanism of the toll device, so that the independent operation of the releasing device is guarded against.

I will describe myinvention more particularly and explain further features thereof by reference to the accompanyingdrawing,which is a diagram illustrating by means of conventional symbols a telephone-line extending from a substation to a central office, together with that portion of the apparatus at the central office which is concerned in the operation of my improved service-meter.

The drawing represents two telephone tolllines extending from substations A and B to acentral office O. The telephone-line extends in two limbs 1 2 from the substationto the line-springs of a jack at the central office and is provided with the usual line-signal apparatus, which is well known in the art. At the substation the telephones and accessory signal-receiving apparatus are included in bridges of the line-circuit, and the usual telephone-switch is provided for controlling the circuit through the telephone apparatus. Two switch-keys a b are provided at the substation, each comprising a movable switch-lever normally resting against an upper contactanvil, but adapted when depressed to break connection therewith and engage a lower alternate contact-anvil. The lever of key a is connected to the limb 1 of the telephone-line, and the lever of key I) is connected through the substation apparatus and switch-hook with the other limb 2 of the line. The normal restingcontacts of the keys are connected together, thus completing the circuit, and the lower contacts of both are connected to earth. Each key when depressed is thus adapted to open the circuit between the two limbs of the line and ground the limb with which it is connected. At the central office a pair'of plugs 0 dis provided, the two plugs being united by the link conductors 3 4 5 6 of a cord-circuit, whereby any two lines may be connected together by inserting the plugs into the spring-jacks of their respective lines. The plug 0 is the answering-plug and the other the calling-plug. Each plug has the usual tip, ring, and sleeve contacts 0 c c d d (1 respectively, the tip and ring contacts forming the terminals of the link conductors and adapted to engage the short and long springs, respectively, of any jack into which the plug may be thrust, while the third contact of each plug engages the test-ring of the jack.

A repeating-coil e is interposed in the plugcircuit, and a central battery f is bridged across the circuit between the windings of said coil. A loop is thus formed between the tip and ring contacts ofeach plug, each loop including serially the battery fand two of the windings of the repeating-coil. The normal loop-circuit from tip to ring of plug 0 is I made up of conductor 3, winding e, battery f, winding 6 and conductor-5, and the loop from tip to ring of plugd is made up of conductor 4, winding a battery f, winding 6 and conductor 6. The two plugs are thus united inductively as well. as conductively through the repeating-coil.

A blocking-switch g is provided for making certain changes in the plug-circuit connections, the principal change being to connect winding 6 with winding (2 directly instead of through the battery, so that both conductors 3 and 5 will be connected in multiple branches from the lower pole of the battery. The upper pole of said battery is permanently connected toearth or other return-conductor.

A local circuit from the free pole of batteryfis completed in registering-contacts of each plug and any jack into which it maybe inserted, such local circuit including a'supervisory signal-lamp'and the cut-off relay of the line with which connection is made. The portion of the local circuit from batteryf to plug 0 is made up of the conductor 7, a resistance t, and a supervisory lamp h, and the portion of the local circuit to plug (1 is formed by conductor 8, including the supervisory lamp h. The lamps h h are provided with shunts 9 10, which are controlled by supervisory relays 7t included in the link conductor 5 6 between the. battery connection and the plugs c and d, respectively. Said relays are thus located in the path of current from said battery to the lines with which the plugs may temporarily be connected and are controlled by the switches at the substations of such lines.

A relay Z is included in the cord-strand 3 between the tip of plug'c and the battery connection, and a local circuit 11 from the free pole of the batteryf to earth, including a tripping-magnet m, is controlled jointly by the relays kand Z. This local circuitis closed by the simultaneous excitement of relay Z and inert condition of relay is and may be traced from the batteryf through a portion of conductor 7, including the resistance '6, to the armature of relay 70, from the back contact of said armature to the armature of relay Z, and from the front contact of relayl through the helix of magnet m to earth.

The switch g is provided with three contactsprings g g 9 All three springs are arranged to be simultaneously depressed by a plunger, and each is adapted when so depressed to engage an alternate or front conmally closes the circuit of said conductor to the winding 6 and grounded pole of the battery f, but when depressed transfers the connection of said conductor directly to winding e and so to the other or free pole of the battery, thus bringing both tip and ring strands 3 and 5 into multiple branches from the battery. Spring 9 is connected with the third contact of the answering-plug 0 through a resistance adapted to shunt the supervisory lamp h and normally establishes the shuntcircuit 9 to the front contact of the relay is, said shunt being then completed when the armature of relay k is drawn up. In its alternate position spring g is connected by a conductor 13 directly to the armature of relay k. The spring g when depressed closes a path 12 from batteryf directly to the front contact of relay is to short-circuit the resistance 7;. The resistances, battery, and lamp h are so proportioned to one another that said lamp will light when resistance iis short-circuited, even though the shunt 9 be closed about the lamp. The plunger of the key g has a lug which is adapted to be engaged by a detent m, operated by the armature of magnet 1%. When the plunger is once depressed, it is set or held by the detent until the magnet m shall beexcited and the detent Withdrawn. When the plunger is released, the springs will return to their normal positions. In order that the magnet m may get current, the relay 7c must be inert and relay Z excited. Such a condition-can only be brought about by the operation of the switch-key a of the toll device at the substation.

It is understood, of course, that the plugcircuit may be equipped with the usual ringing and listening keys with their accessory apparatus; but these are omitted from the drawing for the sake of clearness.

The operation of the system may be traced as follows: \Vhen a subscriber desires his line to be connected with some other line for conversation, he transmits a signal to the central office in the usual way by taking his telephone from its switch-hook, and thus closing the circuit through the line-relay, which draws up its armature and brings about the lighting of the line-signal lamp. The centraloffice operator responds to the signal by inserting her answering-plug c in the springjack of the calling-line and by bringing her telephone into circuit learns the number of the line to which connection is desired.- Having secured this information, the operator thereupon inserts the other plug cl of the pair into the jack of the line wanted and then sets the key g, at the same time telling the calling party to operate his toll device. By setting key g both sides 3 5 of the portion of the plug-circuit leading to the answering-plug are connected in multiple to the free pole of the grounded battery f, and the mechanism is locked in that condition by the detent m. Although the supply of current for the callmay still hear in his receiver any sounds transmitted from the called station, since a complete circuit for the telephone-currents is still established between the two stations by way of the repeating-coil e in the plug-circuit. The calling subscriber may therefore wait until the called party answers before he complies with the operators request to actuate his toll device. When the called party answers, the calling subscriber after hearing his response can instantly put his telephone in operative condition by depressing the key a. This breaks the line-circuit and grounds the limb 1 of the line, so that relay Z receives current, while relay does not, the result being that the localcircuit 11, controlled jointly by said relays, is closed and the magnet m in said circuit is excited. The magnet m in drawing up its armature removes the detent m and restores the switch 9 to its normal position, so that the battery f is again included in a bridge of the calling-line. If for any reason the calling party should desire to signal the central-office operator before .the

called party answers, this may be accomplished by depressing the key I). The efiect of this is to close the circuit of conductor 2 to ground, while leaving conductor 1 open. Relay 6 is therefore left inert; but relay 7c is excited and closes the short circuit 12 about the resistance 7;, so that the signal-lamp h is lighted by the increased current. Should the calling subscriber attempt to restore the operative condition of his transmitting-telephone by merely touching a grounded wire to one of the line-terminals of his apparatus, both relays will be excited and the circuit 11 will not be completed. Thelamp h, moreover, will be lighted to attract the attention of the operator, since the short circuit 12 will be closed by relay is.

I claim- 1. The combination with a telephone-line extending from a substation to a central office, of a blocking-switch at the central oftice, a magnet connected with the line at the central office, mechanism controlled by said magnet for restoring the blocking-switch, a toll device at the substation and means controlled in the operation of the toll device for determining the flow of current through said magnet independent of the blocking-switch.

2. The combination with a telephone-line extending from a substation to a central office, of a transmitting-telephone at the substation of the line, a source of current connected with the line at the central office, adapted to supply current to said transmitting-telephone, means at the central office for making connection between said telephoneline and another line, a blocking-switch at the central office adapted when set to interrupt the flow of current from said battery through the subscribers transmitter, a toll device at the substation to be actuated by the subscriber, and means controlled in the oping-subscribers transmitter is now cutoff, he i eration of said toll device for restoring said &

blocking-switch to reestablish the flow of current through said transmitter, substantially as set forth.

3. The combination with a telephone-line extending in two limbs from a substation to a central office, of a transmitting-telephone connected in circuit between the limbs of the line at the substation, a source of current normally included in a bridge of the line at the central oftice, for supplying current to said transmitting-telephone, a blockingswitch at the central office adapted when set to disconnect one limb of the line from its normal battery connection, whereby the flow of current through the transmitting-telephone is interrupted,vmeans controlled by the flow of current in the other limb of the line for releasing said blocking-switch and thereby restoring the normal circuit connections of the battery with the line, and a switch at the substation for completing the circuit from the aforesaid battery through said last-mentioned limb of the line.

4. The combination with a telephone-line extending from a substation to a central office, of a transmitting-telephone in a bridge of the line at the substation, a source of current in a bridge of the line at the central office, adapted to supply current to said transmitting-telephone, a blocking-switch adapted to be set at the central office for interrupting the flow of current from said battery through the transmitter, a magnet connected with the line and mechanism controlled thereby for restoring said blocking-switch, and means at the substation of the line, for determining the flow of current through said magnet independent of said blocking-switch, substantially as described.

5. The combination with a signal-circuit including serially a source of current f, a resistance i and a signal h, of a shunt 9 about said signal, a relay in controlling said shunt, a switch 9 adapted when set to open said shunt 9, and to close a second shunt 9, 13, about said signal independent of said relay, and a shunt 12 about the resistance '5 brought under the control of the relay when said switch is set, substantially as described.

6. The combination with two united telephone-lines having transmitting and receiving telephones in bridges at the respective substations thereof, of a source of current normally connected in a bridge of the united lines for supplying current to the substationtransmitters, an induction device, a switch at the central oftice adapted to block one of said lines by disconnecting one limb thereof from its normal connection with said source of current,,said source being left connected between the blocked line and a return-conductor, the lines being telephonically united through said induction device, but the transmitter of the blocked line being deprived of current for its operation, a toll device for the blocked line, adapted for actuation by the subscriber, a switch actuated in the operation of the toll device for controlling the circuit of said source of current through the blocked line and the aforesaid return-conductor, and a responsive device at the central office in the last-mentioned circuit.

7. The combination, with two line conductors, of a source of current, one pole whereof is connected to a return-conductor, relays one in each of said line conductors, a signal controlled by one of said relays, a local circuit controlled by both of said relays jointly, closed in the normal switch-contacts of one relay and the alternate contacts of the other, a responsive device in said local circuit, and switches for independently completing the circuit of either line conductor.

8. The combination with atelephone-line extending in two limbs from a substation to a central office, of a source of current normally connected in a bridge of the line at the central office for supplying current to the substation, one pole of said source being connected to a return conductor, a blockingswitch adapted to be set to connect both limbs of the line with the free pole of said source, magnets, one in the path of current to each line conductor, a toll device at the substation, a switch actuated in the operation of said toll device for opening the circuit of one limb of the line and connecting the other to the return-conductor, and a restoring device for said blocking-switch, controlled jointly by said magnets and brought into operation by the simultaneous excitement of one magnet and inert condition of the other.

In witness whereof I hereunto subscribe my name this 18th day of December, A. D. 1901.

- \VILLIAM W. DEAN.

Witnesses:

DE Wrr'r G. TANNER,

W. W. LEAOH.

IOO 

